An IC card is made of a plastic support with a hole or recess wherein a microchip micro module is mounted and coupled to a connection interface that can be a contacting instrument, printed circuit micro module IC, or an antenna. The microchip provides calculation functionality and data storage while the micro module of the antenna allows the microchip to dialogue with a special reading terminal usually connected to a computer by a serial interface, parallel interface, USB interface, or gate, etc. The IC cards can be of the contact or contactless type according to the type of connection interface existing between the microchip and the external world. The first have a microchip micro module through which they receive the power supply and dialogue with the outside if inserted in a suitable terminal device, called IC card reader. The second also have an antenna that is connected to the micro module and reacts an electromagnetic field being present and emitted by a special reading/writing device in the band of the radio-frequencies, allowing the microchip to exchange data with the outside, provided that the antenna is at a minimum distance from the reading/writing device. Both the dual-interface IC card offer the contact and contactless interfaces and, therefore, the communication with the microchip can occur indifferently by means of either the one or the other. This feature allows to integrate on the same IC card both complex applications such as those of digital form typical of the contact IC cards, and simpler and faster ones, such as those of control of the access to reserved areas, which exclusively require wireless memory accesses.
An approach is described in the US patent application 2007/0152072 filed by the same Applicant. By way of example, the annexed FIG. 1 shows an exploded view of a generic IC card 10, comprising a plastic support 1 with a hole or recess 6, a micro module 2 and a microchip 3 incorporated in the micro module 2. In particular, the micro module 2 comprising the microchip 3 and glued in the hole or recess 6 through an epoxy resin 9 used as glue. More specifically, as shown in the annexed FIGS. 2a and 2b, the micro module 2 comprises a plurality of conductive areas a1, . . . an, glued through epoxy resin glues 9 and the microchip 3 which is part of the micro module is electrically connected through bonding wires to the conductive areas of the same micro module 2. Everything is sealed in the hole 6. Some of these conductive areas a1 . . . ak are connected through a corresponding plurality of bonding wires w1 . . . wj to the microchip 3 in a plurality of contact points c1 . . . ck.
These contact points c1 . . . ck supply the communication path between an external reading writing device 4 and the microchip 3. In particular, the communication between an external wireless writing/reading device 8 and the IC card 10 occurs without contact when the IC card is provided with an antenna 5 positioned inside the plastic support 1 and connected to the contact points c1 . . . ck through a pair of pads p1, p2, as schematically shown in the annexed FIG. 3. The antenna sends and receives electromagnetic waves to and from a coupled antenna 7 included in the external wireless writing/reading device 8. In this case, the microchip 3 is supplied through electromagnetic induction by the external device 8.
The IC card takes its intelligence from the integrated microchip through silicon technology. In particular, with reference to FIG. 3, at present the contacts between the pads of the micro module 2 and the pads of the antenna 5 are realized by using the “Anisotropic Conductive Film” (ACF) technology or, alternatively, the “Conductive Resin” technology. Both include realizing the contacts with a resinous matrix in which conductive silver particles are mixed which realize the conduction through contact. The annexed FIG. 4 shows the section of an IC card 40 comprising an antenna 45 comprising a pad p41 and a pad p42 which contact the pads c41 and c42 of the micro module 42 through a first and a second bump 46 and 47 of conductive resin or of conductive anisotropic film. In this type of IC card, however, remarkable problems of the conduction are caused by thermal, mechanical, chemical stresses linked exactly to the use of conductive films or resins.
Despite these advances in the prior art, it would still be desirable to devise a method for realizing a double interface or dual interface IC card, having such structural and functional characteristics so as to realize a good conduction overcoming the limits and/or drawbacks of the dual interface IC cards of the prior art.